CH701901A2 - Process for deasphalting and extracting hydrocarbon oils. - Google Patents

Abstract

Disclosed herein are methods for deasphalting and extracting a hydrocarbon oil. The methods (100) include providing an oil comprising asphaltenes and / or other impurities (101), combining the oil with a polar solvent and an extractant to provide a mixture (102) and applying a stimulus to the mixture (103) at least part of any asphaltenes and / or impurities in the oil precipitate from the oil.

Description

background

Petroleum is the world's major source of hydrocarbons used as fuels and petrochemical feedstocks. Because of the presence of contaminants, crude oil is rarely used in the form produced at the well site, but is typically converted in oil refineries into a wide range of fuels and petrochemicals that are suitable for their intended end uses.

While compositions of natural petroleum or crude oils vary significantly, all raw materials contain sulfur compounds. In general, sulfur concentrations in crude oils range from about 0.5% to about 1.5%, but may vary up to about 8%. Upon combustion, sulfur-containing compounds are converted to sulfur oxides (SOx), which are considered to be environmental pollution. The catalytic oxidation of sulfur and the subsequent reaction thereof with water can lead to the formation of sulfuric acid mist and thereby also contribute to particle emissions. Thus, such raw materials typically must be desulfurized to yield products that meet performance specifications and / or environmental standards.

Vanadium may also typically be present in crude oils, mainly in the form of porphyrin and asphaltene complexes. In some raw materials, depending on the source of the raw material, the vanadium content may reach 1200 ppm and the porphyrin vanadium content may vary from about 20% to about 50% of the total vanadium content. The vanadium present in the raw material has an adverse effect on refinery operations, typically by affecting the efficacy of catalysts typically used in catalytic cracking, hydrogenation and hydrodesulfurization. Further, vanadium present in fuel oil combustion products catalyzes the oxidation of sulfur dioxide to sulfur trioxide, resulting in the formation of acid rain. Vanadium combustion products, V2O5, can adhere to surfaces, resulting in corrosion that can be problematic in some applications.

Since some asphaltenes tend to form coke and / or consume large quantities of hydrogen, deasphalted oil is typically used as a feedstock in the catalytic cracking process. Conventional methods include the use of propane to deasphalt the raw material distillation residue or a residual oil solvent extraction (ROSE) process that utilizes light hydrocarbons selected from propane, n-butane and p-pentane. Both may also result in the removal of a portion of the asphaltenic vanadium, nitrogen and / or sulfur.

However, these conventional methods of deasphalting and demetallization may be suboptimal. Thus, both require very large amounts of solvent in relation to the hydrocarbon feedstock to be treated and produce large asphaltene streams. In addition, their efficiencies and yields may be unsatisfactory in some commercial applications. Finally, these conventional processes are typically unable to separate metals that have not been completely eliminated with the asphaltene fraction, e.g. Vanadium.

Effective and more cost effective methods of removing asphaltenes and metals, e.g. Sulfur and vanadium from hydrocarbon oils are therefore necessary.

Short description

[0008] Methods for deasphalting and extracting a hydrocarbon oil are provided herein. The methods include providing an oil comprising asphaltenes and / or other contaminants, combining the oil with a polar solvent and an extractant to provide a mixture, and applying a stimulus to the mixture so that at least a portion of any asphaltenes and / or Impurities in the oil will precipitate out of the oil.

Drawing

These and other features, aspects, and advantages of the present invention will become better understood upon reading the following detailed description with reference to the accompanying drawings, in which like numerals represent like parts throughout the figures, wherein:

FIG. 1 is a flowchart schematically illustrating one embodiment of the present method; FIG.

FIG. 2 is a flowchart schematically illustrating another embodiment of the present method; FIG.

FIG. 3 is a flowchart schematically illustrating another embodiment of the present method; FIG.

Fig. 4 is a flowchart schematically illustrating another embodiment of the present method;

Fig. 5 is a flowchart schematically illustrating another embodiment of the present method;

Fig. 6 is a flow chart schematically illustrating another embodiment of the present method;

Fig. 7 is a flowchart schematically illustrating another embodiment of the present method.

Detailed description

Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. The terms "first," "second," and the like, as used herein, do not denote any order, set, or meaning, but are used to distinguish one element from another. The terms "one" and "one" do not denote a limitation of quantity, but designate the presence of at least one of the named things, and the terms "front," "back," "bottom," and / or "top," unless otherwise noted , for convenience of description only, and are not limited to any position or spatial orientation. Where ranges are disclosed, the endpoints of all ranges directed to the same component or property are inclusive and independently combinable (eg, ranges of up to about 25 weight percent, or, more specifically, about 5 weight percent to about 20% by weight "excludes the endpoints and all intermediate values of the ranges from about 0% to about 25% by weight, etc.). The modifying term "about" used in conjunction with a set includes the value mentioned and has a meaning dictated by the context (eg, includes the degree of error associated with the measurement of the particular set) ,

[0020] Methods for deasphalting and extracting a hydrocarbon oil are provided herein. The methods include providing an oil comprising asphaltenes and / or other contaminants, combining the oil with a polar solvent and an extractant to provide a mixture, and applying a stimulus to the mixture such that at least a portion of any asphaltenes and / or contaminants in which oil precipitates out of the oil.

The methods disclosed herein may be advantageously applied to any hydrocarbon oil or a mixture of one or more hydrocarbon oils comprising asphaltenes and / or other impurities. Exemplary hydrocarbon oils useful in the present invention include, but are not limited to, liquid oils derived from bitumen (often referred to as tar sands or oil sands), petroleum, oil shale, coal, as well as synthetic crude oils produced by liquefaction of Coal, heavy crude oils and residual oil fractions of petroleum refining, such as residues or fractions produced by atmospheric and vacuum distillation of crude oil. In some embodiments, heavy oils are used in the present processes.

The deasphalted and extracted by the present method desirably hydrocarbon oil is mixed with a polar solvent which has no significant solubility for the oil (for example, ~ <1% of the oil dissolves in the solvent). Any polar solvent may be used and examples of suitable polar solvents include, but are not limited to, dialkyl ethers, ethyl ether solution, 2-ethylhexyl vinyl ether, isobornyl methyl ether, 1,2-dichloroethyl ethyl ether, 2-methoxyethanol, 2-ethoxyethanol, 2-methyl-2-propenylphenyl ether , 3,3-oxydipropionitrile, 2-cyanoethyl ether, acetonitrile, nitromethane, ethanol, methanol and the like. In some embodiments, an ether may desirably be used as the polar solvent and, more particularly, in some embodiments, a diethyl ether may be used.

The ratio of polar solvent to heavy oil is desirably sufficient such that the hydrocarbon oil / polar solvent mixture reduces the initial viscosity of the hydrocarbon oil by about 30-90%. Ratios of polar solvent to hydrocarbon oil expected to be capable of providing the desired viscosity range from about 0.5: 1 to about 10: 1, or from about 1: 1 to about 2: 1 , Optionally, the used polar solvent can be completely or partially recovered and recycled for these or other applications. In embodiments where desired, the polar solvent can be recovered, e.g., by evaporation and subsequent condensation.

Advantageously, an extractant is added to the mixture and this can either be added to the polar solvent prior to mixing with the hydrocarbon oil or it can be added to the mixture after the polar solvent and hydrocarbon oil have been contacted or both. Suitable extractants are desirably substantially soluble in the polar solvent and substantially insoluble in the hydrocarbon oil. Suitable extractants may typically facilitate the precipitation of any impurities in the hydrocarbon oil. Examples of suitable extractants include Lewis acids, that is, metal halides such as chlorides, bromides, iodides. In some embodiments, the extractant (s) may comprise a metal chloride, such as, for example, ferric chloride.

To assist in the precipitation of the asphaltenes and / or impurities from the hydrocarbon oil, a stimulus is desirably applied to the mixture. The stimulus applied may be any stimulus useful for this purpose, and such stimuli include, but are not limited to, heating, shaking, stirring, vibrating, centrifuging, sonication, combinations of these, and the like. Further, any amount of the stimulus may be employed and effective amounts thereof will be readily determined by one skilled in the art. For efficiency, the amount of stimulus applied can be only the amount required to achieve at least partial precipitation of asphaltenes and / or impurities from the hydrocarbon oil, and continued application of the stimulus beyond the point when precipitation stops from the hydrocarbon oil is typically not necessary or useful.

In some embodiments, the mixture is desirably subjected to decantation, centrifugation, sonication, filtration, or combinations thereof, and in some embodiments, the mixture may be subjected to a period of centrifugation sufficient to precipitate a substantial portion of any asphaltenes and / or impurities in the hydrocarbon oil.

The present process desirably removes a significant portion of any asphaltenes and / or impurities within the hydrocarbon oil prior to application of the process. Asphaltenes are molecular substances found in crude oil and consist mainly of carbon, hydrogen, nitrogen, oxygen and sulfur as well as trace amounts of vanadium and nickel. The C: H ratio is about 1: 1.2, depending on the asphaltene source. Asphaltenes are operationally defined as the n-heptane (C7H16) insoluble, toluene (C6H5CH3) soluble component of a carbonaceous material, such as crude oil, bitumen or coal. Asphaltenes have been shown to have a distribution of molecular masses in the range of 400μ to 1500μ at a maximum around 750μ.

The present process also advantageously removes at least a portion of any other impurities in the hydrocarbon oil. The particular impurities and their concentration (s) in the hydrocarbon oil may depend on the geographic source of the hydrocarbon oil as well as the form and prior treatment (if any) of the hydrocarbon oil. Typically, such impurities may include those comprising nickel, sulfur and / or vanadium, that is, the impurities may include any ions, salts, complexes and / or compounds including nickel, vanadium and sulfur. Examples of vanadium-comprising impurities which can be removed by the present process include, but are not limited to, vanadium porphyrins and oxides such as, for example, vanadium pentoxide. Examples of impurities comprising nickel include nickel porphyrins, salts, etc.

In one embodiment, the impurities comprise organic sulfur-containing compounds, such as alkyl sulfides or aromatic, sulfur-containing compounds. Such embodiments are particularly advantageous because conventional methods are incapable of removing both asphaltenes and sulfur impurities. Examples of organic sulfur-containing compounds which typically can contaminate hydrocarbon oils and which are desirably removed therefrom include thiophene and its derivatives. Exemplary derivatives of thiophen include various substituted benzothiophenes, dibenzothiophenes, phenanthrothiophenes, benzonaphthothiophenes, thiophenesulfides and the like. In some embodiments, the initial sulfur content of the hydrocarbon oil is reduced by at least about 50% or even at least about 75% or even at least about 90% by the present process.

Advantageously, the application or removal of heat and pressure are not required for the practice of the present method. However, the use of either or both may facilitate the precipitation of any asphaltenes and / or other impurities within the hydrocarbon oil and so the present process may optionally include them. If desired, the hydrocarbon oil, polar solvent and / or mixture may be brought to a temperature at which the solvent does not freeze, typically at a temperature of at least about 10 ° C or from about 20 ° C to about 50 ° C or even from about 20 ° C to about 35 ° C. The hydrocarbon oil, polar solvent, and / or mixture may also be pressurized to at least about 1 atmosphere, or from about 1 atmosphere to about 5 atmospheres, or even from about 1 atmosphere to about 2 atmospheres.

The asphaltenes thus precipitated from the hydrocarbon oil and / or impurities can then be removed from the hydrocarbon oil. Although it is expected that the mixture will be able to self-separate, the separation of the mixture into the liquid hydrocarbon oil phase and the solid asphaltene / impurity phase may be promoted by the application of one or more stimuli as discussed above ,

After separation, the layers may be prepared by any suitable extraction method or apparatus, as known in the art, such as by decantation, in a batch-wise batch process, by continuous decantation, or by continuous centrifugation, as known in the art to be separated. Thereafter, the hydrocarbon oil treated by the disclosed process may be delivered to a point of use, or it may be subjected to further treatment, or it may be treated again by one or more stages of the disclosed process. Thus, for example, the polar solvent can be removed from the bottom phase along with the asphaltenes and further separated by evaporation and condensation and recycling either for use in the present process or for downstream processes. Or the hydrocarbon oil can be treated again by all or part of the present process. As those skilled in the art will appreciate, the number of applications of the process may depend on the desired purity of the final hydrocarbon product, and one or more of the contacting stages may be repeated until the desired purity is substantially achieved.

It is expected that the present process will be cheaper and less complicated than conventional processes for removing asphaltenes and / or impurities from hydrocarbon oils, such as, for example, hydrodesulfurization, hydroentlation or metallization processes. Further, the present method makes use of materials that are readily available in mass quantities. It is expected that the present process will be capable of removing at least similar amounts and desirably larger amounts of asphaltenes and / or impurities than those conventional techniques.

For example, the disclosed method is capable of removing all measurable amounts of asphaltenes. Further, the process is desirably capable of removing substantially all of the sulfur impurities (e.g., to a level of less than about 1 wt%) from a hydrocarbon oil having a sulfur content of greater than 3%. This is particularly advantageous because conventional methods of deasphalting hydrocarbon oils can not also remove sulfur impurities or at least can not remove sulfur impurities from levels above about 3% to levels below 1% by weight. Aspects of the present invention are particularly useful for gas turbine applications where it is often desirable to reduce the level of sulfur contamination from 4% by weight of sulfur (or more) to less than about 1% by weight of sulfur. The present process is also capable of containing substantially all vanadium-containing impurities (eg, to a level of less than about 10 ppm or, in some embodiments, less than 1 ppm by weight, vanadium) from a hydrocarbon oil, which has a vanadium content of more than 1200 ppm.

Referring to Figure 1, an embodiment of the disclosed process for removing asphaltenes and / or impurities from a hydrocarbon oil in flow form is shown. More specifically, Figure 1 shows method 100 wherein a hydrocarbon oil comprising asphaltenes and / or other step impurities is provided at 101. The impurities removable by process 100 include one or more of asphaltenes, sulfur and / or vanadium impurities and molecules containing sulfur, vanadium and nickel.

The hydrocarbon oil is combined with a polar solvent and an extractant as shown at step 102. The polar solvent may comprise any suitable polar solvent in which the desired extractant is soluble and thus may depend on the choice thereof. Typically, extractants capable of facilitating the precipitation of impurities comprising, for example, sulfur and vanadium include those comprising Lewis acids and polar solvents in which they are soluble include dialkyl ethers, ethyl ether solution, 2-ethylhexyl vinyl ether, isobornyl methyl ether , 1,2-dichloroethylethyl ether, 2-methoxyethanol, 2-ethoxyethanol, 2-methyl-2-propenylphenyl ether, 3,3-oxydipropionitrile, 2-cyanoethyl ether, acetonitrile, nitromethane, ethanol, methanol. The ratio of polar solvent to hydrocarbon oil may be from about 0.5: 1 to about 10: 1, or from about 1: 1 to about 2: 1.

On the mixture of hydrocarbon oil, polar solvent and extractant, a stimulus is applied in step 103. Any stimulus that facilitates the precipitation of hydrocarbon oil contaminants can be used, including, for example, heat, shaking, stirring, vibrating, centrifuging, sonicating, filtering, or combinations thereof. Of these, centrifugation and / or sonication may be used in certain embodiments. For example, centrifuging at at least about 500 rpm or 2500 rpm or more may be sufficient for at least about 1 minute or 20 minutes to assist precipitation of hydrocarbon oil contaminants.

Another embodiment of the present method is shown in FIG. As shown in Figure 2, the extractant may be added to a mixture comprising the hydrocarbon oil and the polar solvent. More particularly, method 200 includes providing a hydrocarbon oil desirably having asphaltenes and / or impurities to remove in step 201. At step 202, the hydrocarbon oil is combined with a polar solvent to provide a mixture and the extractant is then added to step 201 203 added. The desired stimulus is then applied at step 204.

Or, as shown in Figure 3, the extractant may be combined with the polar solvent prior to mixing it with the hydrocarbon oil. Process 300 comprises providing the hydrocarbon oil which is desirably subject to step 301 of the present process. At step 302, the desired polar solvent is mixed with the desired extractant. Then, at step 303, the hydrocarbon oil is combined with the polar solvent / extractant to provide a mixture. The desired stimulus is applied to the mixture at step 304.

The present method may also include removing the precipitated asphaltenes and / or impurities from a mixture as shown in FIG. 4. More particularly, and as shown in FIG. 4, method 400 includes providing hydrocarbon oil at stage 401, which is desirably subject to the present method. The hydrocarbon oil is combined at stage 402 with the desired polar solvent and extractant to provide a mixture. Then, at step 403, a stimulus is applied to the mixture and causes at least a portion of the asphaltenes and / or impurities within the hydrocarbon oil to precipitate out of the mixture. The precipitate may then be removed from the mixture as shown at step 404, e.g., by centrifuging and then decanting, etc., the mixture from the precipitate.

In some embodiments, it may be desirable to repeat either the addition stage and / or the stage of applying the stimulus to the mixture or both. Repetition of one or both of these steps can further reduce the amount of asphaltenes and / or impurities in the hydrocarbon oil, so that cleaner fractions can be obtained or one can begin with rougher grades of hydrocarbon oils. Such an embodiment is shown in Fig. 5, where after removal of the precipitate at step 504, the mixture at step 505 is recycled by the process, i.e., the mixture undergoes both an additional stage of combining the mixture with. another amount of polar solvent and extractant at the repeated stage 502 and the application of the stimulus at the repeated stage 503.

Or, after the precipitate has been removed from the mixture (step 604 in method 600), the polar solvent may also be removed therefrom (step 605), e.g. by evaporation, and reuse in the process as shown in FIG. As shown, method 600 includes providing a hydrocarbon oil comprising asphaltenes and / or impurity at stage 601 and combining the hydrocarbon oil with a polar solvent / recycled polar solvent and extractant at stage 602. At step 603, a stimulus is then applied to the mixture to facilitate the precipitation of asphaltenes and impurities from the mixture, and the precipitate is removed at step 604. The polar solvent may be removed from the mixture at step 605 and the recovered polar solvent returned to the process at step 606.

The present process desirably results in the provision of hydrocarbon oil which is substantially free of asphaltenes and / or other impurities and ready for further processing, and this is contemplated and shown in Figure 7. Method 700 at step 701 comprises providing hydrocarbon oil comprising asphaltenes and impurities and combining the hydrocarbon oil with a polar solvent and extractant to provide a mixture at step 702. Then, at step 703, a stimulus is applied to the mixture, resulting in the precipitation of at least a portion of any asphaltenes and / or impurities in the hydrocarbon oil. The precipitated asphaltenes and / or impurities can then be removed from the mixture as shown at step 704 and the hydrocarbon oil subjected to further processing as shown at step 705.

Examples

Comparison: 2.77 g heavy oil (HFO) from Saudi was weighed into a centrifuge tube. 4.31 g of diethyl ether (polar solvent) was added. The tube was shaken vigorously until the contents were well mixed and the oil was "dissolved" in the diethyl ether. The resulting mixture was centrifuged at 2100 rpm for 10 minutes. The residual diethyl ether in the cake at the bottom of the tube as well as the supernatant were dried at room temperature to a constant weight. The remainder was 18.7% by weight. The sulfur in the diethyl ether-free supernatant was measured by X-ray fluorescence (XRF) and found to be 3.5 wt% sulfur. The residual sulfur content is similar to that obtained when petroleum ether is used for deasphalting, that is, this conventional process does not remove sulfur compounds from the HFO to any significant degree.

Example 1: In a 15 ml centrifuge tube, 0.39 g of iron (III) chloride were weighed. 6 g diethyl ether (DEE) was added to dissolve FeCl3. This solution became a solvent for deasphalting and as an S and V marker. 3.52 g of HFO were added. The mixture was shaken vigorously until the HFO appeared to "dissolve" completely in the DEE / FeCl3 solution. The resulting mixture was centrifuged at 2100 rpm for 10 minutes. The residual diethyl ether in the supernatant was dried at room temperature to a constant weight before performing a% S measurement by XRF. The recovered total supernatant was 78% of the starting oil and the residual sulfur was 2.35% by weight.

Example 2: In a 50 ml centrifuge tube, 5.0 g of iron (III) chloride were weighed. 10 g of diethyl ether (DEE) was added to dissolve the FeCl3. This solution became a solvent for deasphalting and S and V labeling agents. 10.0 g HFO were added. The mixture was shaken vigorously until the HFO appeared to "dissolve" completely in the DEE / FeCl3 solution. The resulting mixture was centrifuged at 2100 rpm for 10 minutes. The residual diethyl ether in the supernatant was dried at room temperature to a constant weight before performing a% S measurement by XRF. The residual sulfur was 1.67% by weight.

While various embodiments of the present invention have been shown and described herein, it should be understood that such embodiments are exemplary rather than limiting. Numerous variations, changes, and substitutions will be apparent to those skilled in the art without departing from the teachings of the present invention. It is therefore intended that the invention be interpreted within the full spirit and scope of the appended claims.

[0049] Disclosed herein are methods for deasphalting and extracting a hydrocarbon oil. The methods 100 include providing an oil comprising asphaltenes and / or other impurities 101, combining the oil with a polar solvent and an extractant to provide a mixture 102 and applying a stimulus to the mixture 103 such that at least a portion of any asphaltenes and / or Impurities in the oil will precipitate out of the oil.

LIST OF REFERENCE NUMBERS

[0050] <Tb> 100 <sep> Process <Tb> 101 <sep> Level <Tb> 102 <sep> Level <Tb> 103 <sep> Level <Tb> 200 <sep> Process <Tb> 201 <sep> Level <Tb> 202 <sep> Level <Tb> 203 <sep> Level <Tb> 204 <sep> Level <Tb> 300 <sep> Process <Tb> 301 <sep> Level <Tb> 302 <sep> Level <Tb> 303 <sep> Level <Tb> 304 <sep> Level <Tb> 400 <sep> Process <Tb> 401 <sep> Level <Tb> 402 <sep> Level <Tb> 403 <sep> Level <Tb> 404 <sep> Level <Tb> 500 <sep> Process <Tb> 501 <sep> Level <Tb> 502 <sep> Level <Tb> 503 <sep> Level <Tb> 504 <sep> Level <Tb> 505 <sep> Level <Tb> 600 <sep> Process <Tb> 601 <sep> Level <Tb> 602 <sep> Level <Tb> 603 <sep> Level <Tb> 604 <sep> Level <Tb> 605 <sep> Level <Tb> 606 <sep> Level <Tb> 700 <sep> Process <Tb> 701 <sep> Level <Tb> 702 <sep> Level <Tb> 703 <sep> Level <Tb> 704 <sep> Level <Tb> 705 <sep> Level

Claims (10)

A method (100) of deasphalting and extracting a hydrocarbon oil, comprising providing an oil comprising asphaltenes and / or other impurities (101), combining the oil with a polar solvent and an extractant to provide a mixture (102) and applying stimulating the mixture (103) so that at least a portion of any asphaltenes and / or impurities in the oil precipitate out of the oil. 2. The method of claim 1, wherein the polar solvent is dialkyl ether, ethyl ether solution, 2-ethylhexyl vinyl ether, isobornyl methyl ether, 1,2-dichloroethyl ethyl ether, 2-methoxyethanol, 2-ethoxyethanol, 2-methyl-2-propenylphenyl ether, 3,3-oxydipropionitrile, 2- Cyanoethyl ether, acetonitrile, nitromethane, ethanol, methanol or a combination thereof. The process of claim 1, wherein the ratio of polar solvent to oil is from about 0.5: 1 to about 10: 1. The method of claim 1, wherein the extractant comprises a Lewis acid. The method of claim 1, wherein the stimulus comprises heating, cooling, shaking, stirring, vibrating, centrifuging, sonicating, filtering or combinations thereof. The method of claim 1, wherein the stimulus comprises centrifugation. A process according to claim 1 wherein the impurities comprise sulfur, vanadium, nickel or combinations thereof. A process according to claim 7, wherein the impurities comprise sulfur and vanadium. The process of claim 1, wherein the process reduces the initial sulfur content of the hydrocarbon oil by at least about 50%. 10. The method of claim 1, further comprising removing the precipitate from the mixture.